Intentions in the brain: the unveiling of Mister Hyde.

Is it possible to understand the intentions of others by merely observing their movements? Current debate has been mainly focused on the role that mirror neurons and motor simulation may play in this process, with surprisingly little attention being devoted to how intentions are actually translated into movements. Here, we delineate an alternative approach to the problem of intention-from-movement understanding, which takes "action execution" rather than "action observation" as a starting point. We first consider whether and to what extent, during action execution, intentions shape movement kinematics. We then examine whether observers are sensitive to intention information conveyed by visual kinematics and can use this information to discriminate between different intentions. Finally, we consider the neural mechanisms that may contribute to intention-from-movement understanding. We argue that by reframing the relationship between intention and movement, this evidence opens new perspectives into the neurobiology of how we know other minds and predict others' behavior.